I am trying to build a 2D map for a flat loop using hector mapping . I have no odometry data and therefore, configured mapping_default.launch to use base_link frame in all cases:

<arg name="tf_map_scanmatch_transform_frame_name" default="scanmatcher_frame"/>

<arg name="base_frame" default="base_link"/>

<arg name="odom_frame" default="base_link"/>

Now launching hectorslam with `roslaunch hectorslam_launch tutorial.launch`, map gets created, however, there is a huge drift. Obviously, angles are not accurate at turns. So when it visits the starting point, it can't make a nice overlap. How can I fix/improve this?